Group owner cannot send an invite to a group

[tgxworld (Alan Tan)]

@AlexL

Group owners (who are also moderators in my setup) can send out invites to a forum, but when doing that, they cannot set up adding the invitee to the group they own, the group name field is not available on the invite dialog. Only admins have that field shown.

This is mostly done but I’ll wait till Monday before I review it again and merge in my changes.

https://github.com/discourse/discourse/pull/4983